Alumina fiber aggregate and method for producing the same
AssigneeMitsubishi Chemical Corporation
InventorYusuke Kimura
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Abstract
An alumina fiber aggregate that is formed of alumina short fibers and has been subjected to needling treatment, wherein the alumina short fibers have an average fiber diameter of 6.0 μm or more and 10.0 μm or less and a specific surface area of 0.2 m2/g or more and 1.0 m2/g or less, and a residual percentage (%) of high-temperature-cycle opened gap pressure of the alumina fiber aggregate is 45% or more. A value obtained by subtracting twice the standard error of a length-weighted geometric mean diameter of fiber diameters of the alumina short fibers from the length-weighted geometric mean diameter is 6.0 μm or more. A proportion of alumina short fibers having a fiber diameter of more than 10.0 μm is preferably 5.0% or less on a number basis.
Claims14
An alumina fiber aggregate that is formed of alumina short fibers and has been subjected to needling treatment,
- wherein the alumina short fibers have an average fiber diameter of 6.0 μm or more and 10.0 μm or less and a specific surface area of 0.2 m2/g or more and 1.0 m2/g or less, and
- a residual percentage (%) of high-temperature-cycle opened gap pressure of the alumina fiber aggregate is 45% or more.
The method for producing an alumina fiber aggregate according to claim 14,
- wherein the spinning aid contains at least polyvinyl alcohol A having a degree of polymerization of 1.8×103 or more and 2.4×103 or less and a degree of saponification of 85.0 or more and less than 92.0 and polyvinyl alcohol B having a degree of polymerization of 2.2×103 or more and 3.0×103 or less and a degree of saponification of 92.0 or more and 99.5 or less, and
- the polyvinyl alcohol A and the polyvinyl alcohol B are contained at a mass ratio of 9 to 5:1 to 5, a weighted average of the degrees of polymerization of the polyvinyl alcohol A and the polyvinyl alcohol B is 2.0×103 or more and 3.0×103 or less, and a weighted average of the degrees of saponification of the polyvinyl alcohol A and the polyvinyl alcohol B is 85.0 or more and 95.0 or less.
Dependencies are inferred from the claim text.